Patent GB-278436-A (GB)
Title: Improvements in and relating to shutters and film winding devices for photographic cameras
IPC: G03B19/04
Filed: 1926-07-07
Abstract: 278,436. NiÚll, M. July 7, 1926. Cameras, roll film, with connected action between shutter and changing mechanism; shutters, roller-blind. -In a roll-film camera having an arrangement whereby the film is advanced simultaneously with the setting of a focal plane shutter, the film spool winding pinion 12, Figs. 2 and 4, and the shutter pinion 21 are normally connected by an intermediate wheel 13 which is moved in its own plane out of gear with the shutter pinion 21 for an exposure, but remains in gear with the film pinion 12. A lens flap normally covers the lens, but is automatically operated to uncover it for an exposure. The shutter is of the non-capping variety and can be set for "bulb" or " instantaneous " exposure. The exposure slit can be varied, and the mechanism is such that two successive "bulb" exposures cannot be effected without first resetting the mechanism to the position for an instantaneous exposure. The intermediate wheel 13 is mounted on an arm 14 on the film spool shaft, and is normally maintained in mesh with the pinions 12, 21 by one arm of the spring 16 acting on the projection end 15 of the arm 14. A lever 17 has a projection 17<a> which on actuating the exposure release 20, Fig. 1, moves the end 15, the lever 17 being connected by a slide 19 with the release 20 and with a cam 48, Figs. 1 and 9, and rocking shaft mechanism 46, 47 which operates the spring-controlled lens flap 40 through an angle lever 44 and cord 43, throughout the adjustable range of the lens front. The shutter is set by winding the film spool handle 12<a>. The pinion 21 meshes with a, wheel 22 having a pin 23 which on the first revolution engages behind a freely mounted projection 24 and then carries this with it until the projection 21 is arrested by a fixed stop 25. The loaded pawl 34 acting on the pinion 12 prevents backward movement of the set parts. To alter the exposure slit an internal pinion 27, Fig. 8. normally connecting the shutter blind shaft 29 with the pinion 21 can be drawn out by the milled head 31, and brought into gear with the indicating wheel 32, Fig. 2, and the shaft 29 independently rotated. The pinion 21 is, in the meantime, held by a pawl 27a engaged by a catch Y operable outside the camera, part of the catch forming a cover for the head' 31. The shutter is released for exposure by the disengagement of the movable gear 13 from the, wheel 21, and is operated by an adjustable spring on the lower shutter roller 36. To set the shutter for a " bulb " exposure the pin 49, Figs. 1 and 2, is moved to the left, and moves to the other side of the inverted-V-shaped, end of the spring 16, Fig. 4. The pin carries over with it a slotted arm 50 mounted on the stud 51, and having a nose 52 which engages in front of an arm 53 on the lever 17, and under a sliding piece 54 which is pressed in contact with it by the spring 60. On actuating the release 20, the arm 53 moves the nose 52, raises the piece 54 to intercept the pin 23 at the end of its first revolution. thereby holding the shutter open until released. To prevent a second " bulb " exposure without first resetting the parts for an instantaneous exposure, a slide 55 mounted on the stud 51 by a forked end, has at the upper end a slot 56 engaging a stud 57 on the shaft of the intermediate wheel 13 and also a projection 58 which on a " bulb " exposure moves behind a fixed stud 59, the spring 60 acting to effect this movement of the slide 55. The movement prevents the wheel 13 returning into gear with the shutter pinion 21, until the knob 49 is moved over, thereby engaging a shaped part 62 on the slide 55 and moving it clear of the stud 59. For winding the film independently on loading and unloading, the wheel 13 may be disengaged from the pinion 21 by the handle z, Fig. 1, acting on a projecting piece 55a on the slide 55.